My Build - I blame you lot for this....!

[Jonathan]

I don't fancy cleaning up the machine after that!

I was also experimenting a bit on friday with feedrates on 20mm aluminium plate. I'm using a nearly new 20mm 4 flute HSS cutter. With a maximum cut width of roughly 5mm (plate was allmost to size, just machining the edges), stepdown of 2mm and 2150 RPM I found 720mm/min to be good. It would go faster, but I'm only putting the cutting fluid on with a brush and I didn't want to push it...

For finishing I tried various speeds still at 2150rpm. I left 0.5mm for the finishing pass and did one 20mm deep climb milling pass. I couldn't really see any improvement in finish below 300mm/min, so I stuck with that.

On the first of the attached photos you can see the difference between accidently running the finish pass at 600 compared to <300.